Description
OpenSMTPD before 6.6.4 allows local users to read arbitrary files (e.g., on some Linux distributions) because of a combination of an untrusted search path in makemap.c and race conditions in the offline functionality in smtpd.c.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | opensmtpd | 6.6.4p1-1 | — |
| Debian 13 | opensmtpd | 6.6.4p1-1 | — |
| Debian 12 | opensmtpd | 6.6.4p1-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | opensmtpd | 6.6.4p1-1 | — |
| Ubuntu 18.04 LTS | opensmtpd | 6.0.3p1-1ubuntu0.2 | USN-4294-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | opensmtpd | 5.7.3p2-1ubuntu0.1~esm2 | USN-4875-1 |
| Ubuntu Pro 14.04 LTS | opensmtpd | 5.4.1p1-1ubuntu0.1~esm1 | USN-4875-1 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- OpenSMTPD 6.6.3 - Arbitrary File Read EDB-48139 · remote · Feb 26, 2020
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- USN-4875-1 opensmtpd vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- USN-4294-1 OpenSMTPD vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
References
- https://www.openbsd.org/security.html
- [oss-security] 20200224 Local information disclosure in OpenSMTPD (CVE-2020-8793) mailing-list
- 20200227 Local information disclosure in OpenSMTPD (CVE-2020-8793) mailing-list
- FEDORA-2020-b92d7083ca vendor-advisory
- USN-4294-1 vendor-advisory